export default {
  namespaced: true,
  
  state: () => ({
    // 每个商品的信息对象，都包含如下 6 个属性：
    // { goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state }
    cart: JSON.parse(uni.getStorageSync('cart') || '[]')
  }),
  
  mutations: {
    addToCart(state, goods){
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id);
      
      if(!findResult){
        state.cart.push(goods);
      }else{
        findResult.goods_count++;
      }
      this.commit('m_cart/saveToStorage');
    },
    
    saveToStorage(state){
      uni.setStorageSync('cart', JSON.stringify(state.cart));
    },
    
    updateGoodsState(state, goods){
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id);
      
      if(findResult){
        findResult.goods_state = goods.goods_state;
        
        this.commit('/m_cart/saveToStorage')
      }
    },
    
    updateAllGoodsState(state, newState){
      state.cart.forEach(x => x.goods_state = newState);
      this.commit('m_cart/saveToStorage')
    },
    
    updateGoodsCount(state, goods){
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id);
      
      if(findResult){
        findResult.goods_count = goods.goods_count;
        this.commit('/m_cart/saveToStorage')
      }
    },
    
    removeGoodsById(state, goods_id){
      state.cart = state.cart.filter(x => x.goods_id !== goods_id)
      this.commit('m_cart/saveToStorage')
    }
  },
  
  getters: {
    total(state){
      let c = 0;
      state.cart.map(goods => c += goods.goods_count);
      return c;
    },
    checkedCount(state){
      return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
    },
    checkedGoodsAmount(state){
      return state.cart.filter(x => x.goods_state)
                      .reduce((total, item) => total += item.goods_count * item.goods_price, 0)
                      .toFixed(2)
    }
  }
}